I ran a forum search for "creating expressions" but found no relevant threads. Yet I'm sure this must have been discussed.

How does one create a facial expression without resetting every morph in the head (other than the ones in the expression) to zero? I made some expressions and saved them as .fc2, but when using them they wiped out character morphs, even the DAZ ones like Utopia, Amazon, Young, etc.

I checked the .fc2 file in a text editor and saw that in addition to the expression morphs, there were many, many additional morphs, all set to zero. Seemed like every morph belonging to Vicky. Even the PBMCC channels, which are used to carry user-created FBMs including custom heads.

I checked the .fc2 files from some purchased expressions and none of these extraneous channels were there. In some freebie expressions, however, they were.

The extra channels can be stripped out with a text editor, but it is tedious because the non-expressions are mixed in with the expressions, so it would be quite tedious to do with each expression. 

So how does one quickly get rid of the non-expression channels in .fc2 files, or avoid including them in the first place?